I just bled my under the floor booster too. For one thing, I took a bath in brake fluid while lying on the ground trying to get the thing in place after bench bleeding it. I guess I should have plugged the holes, but the level in the res. stayed high enough so that air didn't get back down in there anyway.

I was having trouble at first too, I was just pressing down on the pedal one time and holding it. The drums bled ok, but the discs weren't. Then I talked to an older guy and he told me to pump them 4 or 5 times and then hold it. That worked.